SAN DIEGO: French Open runner-up Samantha Stosur of Australia was ousted from the 700,000-dollar WTA San Diego Open on Friday, losing a quarter-final 6-4, 6-3 to Italian fifth seed Flavia Pennetta.

Second seed Stosur joined Serbian top seed Jelena Jankovic and Russian third seed Vera Zvonareva on the scrapheap at the 700,000-dollar hardcourt tournament, a tuneup for the US Open that begins on August 30.

Pennetta fired seven aces and blasted 19 winners past Stosur to book a semi-final berth against Svetlana Kuznetsova, who downed US teenager CoCo Vandeweghe 7-5, 6-2.

"It`s a good feeling because she`s one of the best players," Pennetta said. "She has had an unbelievable year. It`s never easy to beat this kind of player."

Kuznetsova, who reached her first semi-final of 2010, said eventually her experience won out over the US youngster, who upset Zvonareva on Thursday night.

"I think I won by experience," Kuznetsova said. "I wasn`t playing my best game. I think she was so confident (from Thursday). It took me time to break her up."

In a battle of unseeded players, Daniela Hantuchova of Slovakia beat Russian Alisa Kleybanova 2-6, 6-4, 6-3. In the semi-finals Hantuchova will face fourth-seeded Agnieszka Radwanska of Poland, who won the last nine games in a 6-2, 6-0 rout of seventh-seeded Israeli Shahar Peer.

While Stosur is one of the tour`s top servers, she didn`t muster an ace and had five double faults.

"She makes a lot of balls and runs everything down," Stosur said. "She really makes you work for every point you win. Sometimes that can be a little bit frustrating."

Vandeweghe, who hails from the San Diego area, took a 5-2 lead in the first set against Kuznetsova, riding the momentum of her victory the night before.

"I thought early on I was kind of beating her with my pace and the heaviness of the ball," she said.

But after Kuznetsova saved a set point, the Russian went on to win five straight games to take the first set.

She put together a string of four games in the second set to lead 5-1 and sealed the match in the eighth game on her third match point.

"I came in a little bit tired from last night, a little heavy legged," said Vandeweghe, who came through qualifying here but said she has received a wild card to play next week at Cincinnati.

"I had a great first set. She`s a two-time Grand Slam champion for a reason."

BDST:1624HRS, August 7, 2010